This ecoregion is the largest on the Arabian Peninsula.
It is a vast desert wilderness stretching from Yemen to the Arabian Gulf and Oman to Jordan and Iraq. It is one of the continuous bodies of sand in the world. Gazelles, oryx, sand cats, and spiny-tailed lizards are just some of the desert-adapted species survive in this extreme environment, which features everything from red dunes to deadly quicksand. The climate is extremely dry, and temperatures oscillate between extreme heat and seasonal nighttime freezes.

This ecoregion holds little biodiversity, although a few endemic plants grow here. Many species, such as the striped hyaena, jackal and honey badger have become extinct in this area due to hunting, human encroachment and habitat destruction[?]. Other species have been successfully re-introduced, such as the endangered white oryx and the sand gazelle, and are protected at a number of reserves. Overgrazing by livestock, off-road driving[?], human destruction of habitat are the main threats to this desert ecoregion.

Type : hyper aridDetailed description : Most of the Rub'al-Khali is classified as hyper-arid. Rainfall is generally less than 35mm per annum and relative humidity low (50% in winter, 15% in summer). Temperatures are about 50°C in summer, with an average temperature of 12°C in winter, though it can go below 0°C. Daily extrems are very important.<br>
Saudi Arabia show lower summer temperatures (around 30°C) with cold winter temperature (around 5°C, with frequent frost), with average rainfall of less than 80 mm.

The Wahiba sands of Oman : an isolated sand sea bordering the east coast

The Rub' al-Khali[?][1] (http://www.alovelyworld.com/webyemen/htmgb/yem027.htm) desert is a sedimentary basin elongated on a southwest to northeast axis across the Arabian shelf. At an altitude of 1000 metres, the rock landscapes yield the place to the ar-Ruba' Al-Khali, vast wide of sand of the Arabian desert, whose extreme southern point crosses the center of Yemen. The sand overlies gravel or gypsum plains and the dunes reach maximum heights of up to 250m. The sands are predominantly silicates, composed of 80 to 90% of quartz and the remainder feldspar, whose iron oxide-coated grains color the sands in orange and red.

The Rub'al-Kali has very limited floristic diversity. There are only 37 species, 20 recorded in the main body of the sands and 17 around the outer margins. Among these 37 species, only one or two are endemic. Vegetation is very diffuse but fairly evenly distributed, with some interuptions of near sterile dunes.
Some typical plants are

Countries : mostly Saudi Arabia, extending into the surrounding countries of Egypt (Sinai), western Iraq, much of southern and eastern Jordan, Syria and northern Saudi Arabia. Bordering the Arabian Gulf, there is an extension into Qatar and, further east, the region covers almost all of Abu Dhabi in the United Arab Emirates (UAE). The Rub'al-Khali crosses over from Saudi Arabia into western Oman and eastern Yemen.

This ecoregion was victim of a massive economic-environmental : the sabotage of Kuwait oil facilities that caused vast oil spills and the release of toxins into the atmosphere in the 1990s.

At the beginning in January 1991 during Gulf War, Iraqi forces released about 11 million barrels of oil from storage tanks and tankers directly into the Gulf. In February, they also destroyed 1,164 Kuwaiti oil wells. It took nine months to extinguish these oil fires. These oil spills contaminated 600 miles of Gulf coast.

Result of the pollution was thousands of water birds death and serious damage to the Gulf's aquatic ecosystem (shrimp, sea turtles, dugongs, whales, dolphins and fish).

The damaged wells also released 60 million barrels of oil into the desert and formed lakes (total surface of 49 square kilometers) which contaminated soil and ground water[?].

====Weaponry====
Weaponry used by the US during the Gulf war[?] also poses a huge risk to the environmental stability of the area. Tank columns in the desert plains may disrupt the fragile stability that exists. The desert soil is protected from erosion by a thin hardened crust. However, in 1991, the passage of US tanks damage the crust and unleashed a massive, slow moving sand dune. Some people fear that this dune could ultimately reach Kuwait City. Another concern is related to the use of radioactive depleted uranium munitions by the A-10 Warthog. Some detractors claim the ammunitions to be a risk for cancer and a source of water contamination[?]. In 1991, the U.S. and NATO dropped nearly 300 tons of depleted uranium on Iraqi targets. The splinters resulting from the explosion contaminated the surrounding soil.